A 4 month old infant with no prior vaccinations is brought to clinic because of paroxysmal coughing spells followed by inspiratory whooping and posttussive vomiting. The responsible organism produces a toxin that increases cyclic AMP by preventing inhibition of adenylate cyclase. This toxin acts by which of the following mechanisms?
- A)ADP ribosylation of Gs
- B)Cleavage of SNARE proteins
- C)Inactivation of elongation factor 2
- D)Activation of guanylate cyclase
- E)ADP ribosylation of GiGABARITO
Explicação
Pertussis toxin ADP ribosylates the inhibitory Gi protein, which prevents down regulation of adenylate cyclase and raises cyclic AMP. The result contributes to lymphocytosis and the classic prolonged coughing illness in unimmunized infants. Ver explicação completa e trilha adaptativa →